This invention relates to a telephone switching system that provides call management based upon call priority. More particularly, this invention relates to a telephone switching system that provides call priority to a telephone station having more than one line of service from the switching system.
Some institutions, such as the military, require telephone service having call priority. In a call priority system, incoming telephone calls to a telephone station are processed in the following manner. For purposes of the present discussion, a telephone station is a telephone set, computer, fax machine, or other piece of telephonic equipment that is a termination point for telephone calls in a system. If the telephone station is not connected to an existing call, the incoming call is processed normally and connected to the telephone station. If the telephone station is already connected to existing call, the following method is used to process the call. First, the priority of the incoming call is determined. If the incoming call has a greater priority than a routine call, a signal is transmitted to the telephone set that indicates a priority call is waiting to connect. The signal is a distinctive beep or other sound transmitted over the voice channels of a telephone set to notify a user of an incoming call with priority. If the incoming call does not have a priority higher than a routine call, a busy signal is returned to the calling party.
In today""s society, it is common for a switching system, such a Personal Branch eXchange (PBX) switch to provide a telephone station with more than one line. For example, a telephone set in each office of a building may have two lines connected to the set. A user may then be actively connected to a call over one line while another call on another line is in an on-hold status. The user may also change the status of a call on a line from active to on-hold. The changes are usually made by pushing a button which sends an out of band signal to the telephone switching system signaling the desired change.
It is a problem to provide a priority call system to a telephone station having more than one connected line. One problem that arises in providing a call priority system to telephone stations having more than one line is a determination of which line has an active call. A second problem is how to a handle a call that has a higher priority level than an active call over the telephone network. There is a need in the art for a system that can solve the above problems.
The above described problems are solved and a technical advance achieved by a system for processing telephone call with call priority for telephone stations having multiple lines. The system of the present invention is provided by applications executed by a switching system that provides telephone service to a telephone station. The following process is executed by the switching system to provide call priority to a telephone station. One advantage of this invention is that the processes described can be performed for an analog telephone set, a digital telephone set, and/or a BRI telephone set.
When an incoming call for an extension of a telephone station connected to a switching is received by the switching system, the switching system determines whether all of the lines available to the telephone station already have a connected call appearing on the line. If there is a line available to the telephone station, the call is connected to the available line and the user is signaled that a new call has been received. If there are no available lines for the telephone station, it is determined whether there is an active call currently connected to the station. If there is not an active telephone call connected to the telephone station, the switching systems returns a busy signal to indicate the telephone station cannot currently accept the call. If the call is an incoming call received over the telephone network the priority of each existing call is compared to the priority of the incoming call. If an existing on hold telephone call has a lower priority level than the incoming call, the existing call with a lower priority is disconnected and the incoming call is then connected over that line.
If all of the available lines are connected to calls and one call is actively connected to the station, the following process is executed when an incoming call has a priority greater than a routine call. The priority level of the incoming call is compared to a priority level of active call. If the priority level of the incoming call is greater than the priority level of the active call, a signal, such as a distinctive tone, is transmitted to the user over voice channels to indicate a priority call. Otherwise, busy signal is returned.
In an alternative embodiment, the following process occurs when a priority call has priority that is less than the active call. If the priority level of the incoming call is less than the priority level of the active call, the priority level of the incoming call is then compared to the priority level of the on-hold calls on the other lines. If a call having a lower priority level than the incoming call is found, the call is disconnected and the incoming call is connected to the line that was handling the disconnected call. The incoming call is then placed in an on-hold status.